The present invention relates to a plate-tilting apparatus. and especially to a plate-tilting apparatus adapted to be used in a semiconductor-manufacturing process.
In the semiconductor-manufacturing process, a wafer needs to be processed through many times of etching and polishing processes. Each of the etching and polishing processes will remove a thin surface layer from the wafer and generate some extraneous or unwanted materials. These contaminants are very harmful to the properties of the semiconductor devices. In order to improve the yield, after every step, wafers need to be cleaned carefully. Nowadays, with the progress of the semiconductor-manufacturing process, not only is the line width of conducting lines in the semiconductor device getting smaller and smaller, but the thickness of wafers is getting thinner and thinner. While the thickness of a wafer is less than 200 xcexcm. it becomes more and more difficult to clean the wafers effectively.
FIG. 1 schematically shows a wafer cassette 10 generally used in the semiconductor-manufacturing process. There are a plurality of slots 101 on the cassette 10 to collect and separate a plurality of wafers 11 therein. When the wafers 11 are cleaning (the cleaning process is shown in FIG. 2), the whole cassette 10 is immersed in and taken out of from some cleaning solutions, such as pure deionized water, in sequence. Finally, the wafers 11 are carefully dried by spraying isopropyl alcohol (IPA) on the surface of every wafer and evaporating IPA under the presence of hot N2 to complete the cleaning process.
Unfortunately. if the thickness of a wafer is quite thin, especially less than 200 xcexcm, the wafers 11 collected in the cassette 10 can not be dried completely. As shown in FIG. 3. the wafers 11 will bend naturally because the thickness of the wafers is much smaller than the width of the slots 101. Furthermore, the electrostatic force will cause adjacent wafers 11 to contact with each other while they are taking out of the cleaning solutions. Therefore, if the wafers are not dried completely, it is very hard to dry the wafers by using IPA and hot N2 such that the cleaning process will be in vain.
It is therefore attempted by the applicant to deal with the above situation encountered with the prior art. It is further desirable that this problem can be solved without requiring expensive equipment or complicated procedures such that the semiconductor-manufacturing process can be conveniently carried out and needs significantly less time to further reduce the production cost of the assembled systems.
An object of the present invention is to provide a novel plate-tilting apparatus adapted to be used in a semiconductor-manufacturing process such that the aforementioned limitations and difficulties encountered in the prior art can be overcome.
Another object of the present invention is to provide a novel plate-tilting apparatus adapted to be used in a semiconductor-manufacturing process such that every wafer can be dried completely even though the thickness of the wafers is less than 200 xcexcm.
The plate-tilting apparatus of the present invention includes a plate having a first edge pivotally connected to a plane surface, and a plate-lifting device connected to a second edge of the plate opposite to the first edge for lifting the second edge of the plate so that the plate can be tilted at an specific angle.
According to the present invention, the plate-lifting device includes a connecting element having a first end connected to the second edge of the plate, a lifting element connected to a second end of the connecting element for lifting the connecting element so as to tilt the plate.
In accordance with the present invention, the lifting element is a motor with a shaft and the connecting element is connected to an end of the shaft.
According to the present invention, the plate-lifting device further includes a controller for precisely controlling the lifting element to tilt the plate to the specific angle.
Preferably, the controller is an electromagnetic valve.
According to the present invention. the plate further includes a locking member for locking a container thereon. The container is preferably a cassette for collecting a plurality of wafers having a thickness less than 200 xcexcm therein.
In accordance with the present invention, the specific angle is an acute angle, especially 9xc2x0.
According to the present invention. the plane surface is a basal plane of a tank used in a semiconductor-cleaning process, and the semiconductor-cleaning process is a drying process using isopropyl alcohol (IPA)
The present invention may best be understood through the following description with reference to the accompanying drawings, in which: